S1: John was a worker at Bread Store, of which I was the manager, when he lived here.
S2: John was a worker at Bread Store, which I was the manager of, when he lived here.
What's the correct usage? ...

I'm writing about a player playing a game and probabilities. I tried to cut down the sentence, so don't concentrate too much on the sense rather than the commas.
Would you write my sentence like this
...

Recently I encountered the phrase "If you know what is QQ then(...)". The writer wasn't a native English speaker(neither me).
First, I thought it should be "If you know what QQ is ...". But then, I ...

I am wondering whether to use a restrictive relative clause such as:
"Multicopters belong to a family of aircraft called rotorcraft , which also includes helicopters, and although they appear to be ...